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Optical Engineering • Open Access

Differential optical transfer function wavefront sensing
Author(s): Johanan L. Codona

Paper Abstract

An image-based technique for measuring the complex field in the pupil of an imaging system is presented. Two point source images, one with a small modification introduced in the pupil, are combined using a simple and non-iterative algorithm. The non-interferometric method is based on the change in the optical transfer function (OTF) giving a differential optical transfer function (dOTF). The dOTF includes two images of the complex pupil field, conjugated and reflected about the position of the pupil modification, leaving an overlap that obscures some of the pupil. The overlap can be minimized by introducing the modification near the edge of the pupil. The overlap region can be eliminated altogether by using a second modification and a third point source image. The pupil field is convolved by the change in the pupil field, so smaller modification areas are preferred. When using non-monochromatic light, the dOTF incurs a proportional radial blurring determined by the fractional bandwidth. We include some simple demonstration experiments, including using a pupil blockage and moving a single deformable mirror actuator as the pupil modification. In each case, the complex wavefront is easily recovered, even when the pupil mask is unknown and the wavefront aberrations are large.

Paper Details

Date Published: 20 September 2013
PDF: 13 pages
Opt. Eng. 52(9) 097105 doi: 10.1117/1.OE.52.9.097105
Published in: Optical Engineering Volume 52, Issue 9
Show Author Affiliations
Johanan L. Codona, The Univ. of Arizona (United States)

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